st: avoiding rounding when using -outsheet-

Can anyone tell me how to keep my data from being rounded to 3 significant
figures when exporting my data from Stata using -outsheet-?

For example, I have an item of data which is 531,123,435 (531 million, 123
thousand, and 435). When I use -outsheet- to create an ASCII file of the
data, this data point becomes 531,000,000 in the ASCII file.

The variable storage type is numeric (double).

What is going on? How can I keep the data from being rounded without
exporting the data as a string variable?